Can you see the pictures for the Val d'Uina tour on
this link? If not please let me know and I'll try to figure out why.
The Val d'Uina tour as listed there is an out and back tour and can be done as a round loop too. It's a stunning tour but not the only one by a long shot.
Within reasonably close distance from Zurich I can recommend the following:
Hoch-ybrig (Contact me directly and I can suggest a way of lengthening the tour.)
Rigi (The descent is a bit steep in places but should be ridable for most)
Rinderweidhorn (Probably the least technical option, depending on how it is ridden)
Wallensee (The descent is technical and psychologically very scary as you are looking 1000m down to the lake from the trail)
In Graubunden
this trail can be continued on to Davos to make a nice Lenzerheide to Davos route taking in the Landwasser river and Viaduct, Wiesen Viaduct and Gorge and Zungenschluct.
Also the Rhineschlucht is a nice tour, but not very physically demanding. (Just realised that I've not got that tour on the site yet but can give you details if you want).
I can give you further information for any of those tours or possibly provide other suggestions too if you want.
Unfortunately on July 9th I'm guiding some people making an MTB movie here in CH so won't be free myself but can help with the planning.